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spudgun range, are we falling short?

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Unread postAuthor: jackssmirkingrevenge » Wed Apr 25, 2012 1:03 am

MrCrowley wrote:The MiniBoy V2? :wink:


Don't tempt me :D

A small data logger GPS I found even gave specs like:
Max velocity: 550m/s
Max acceleration: 4Gs

So I wonder if an epoxy coating will even be enough to protect it.


I think those specs refer to what it can measure, not what it can survive.
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Unread postAuthor: MrCrowley » Wed Apr 25, 2012 1:05 am

Yeah that probably makes more sense :D

I thought 4G might be a bit low for that but then again, how often do you experience more than 4Gs? :P
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Unread postAuthor: jackssmirkingrevenge » Wed Apr 25, 2012 1:23 am

MrCrowley wrote:I thought 4G might be a bit low for that but then again, how often do you experience more than 4Gs? :P


I'm guessing it would experience a bit more than that if you drop it ;) that's several orders of magnitude less than the g-force it woud experience in the barrel, this thing has to be *really* strong. Thing of the poor sods who have to design electronics for something like the Excalibur travelling at Mach 2+...
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Unread postAuthor: MrCrowley » Wed Apr 25, 2012 2:20 am

jackssmirkingrevenge wrote:
MrCrowley wrote:
jackssmirkingrevenge wrote:I think those specs refer to what it can measure, not what it can survive.
I thought 4G might be a bit low for that but then again, how often do you experience more than 4Gs? :P
I'm guessing it would experience a bit more than that if you drop it
Yeah but I assume it's more for measuring how much g-force you experienced in a car accelerating to a particular speed in a set time; in which case 4g is quite a lot.
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Unread postAuthor: dewey-1 » Wed Apr 25, 2012 7:21 am

jackssmirkingrevenge wrote:
Dewey, how would you feel about pouring epoxy on a board like that?

"Terrible"


From where I'm standing though, the RF tracker seems like a better idea. It's cheaper than GPS unit and simcard, and you get two tags so can track two projectiles. I also imagine that the tag electronics are much more compact and simple.

I agree completely!


I have a schematic made for a transmitter and receiver that makes use of the TXC1 and RXB1 that MrC referred to earlier in this post if some wants to build it.

It is probably is very similar to the Guardian Angel.
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Unread postAuthor: jackssmirkingrevenge » Wed Apr 25, 2012 8:18 am

dewey-1 wrote:Dewey, how would you feel about pouring epoxy on a board like that?

"Terrible"


Could you qualify that opinion in terms of how it would negatively affect components?

I would understand that for example an antenna would be affected, or a component with exposed contacts like the sim-card holder, but what about sealed components?

Ifthis can work dipped in oil, then surely epoxy would not destroy it either right? I understand how it would create an insulating layer that would retain heat, but is this an issue on such a scale?
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Unread postAuthor: POLAND_SPUD » Wed Apr 25, 2012 8:25 am

I'm guessing it would experience a bit more than that if you drop it

[youtube]http://www.youtube.com/watch?v=1IXYsDdPvbo[/youtube]
@17:30-21:00
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Unread postAuthor: dewey-1 » Wed Apr 25, 2012 9:33 am

jackssmirkingrevenge wrote:
dewey-1 wrote:Dewey, how would you feel about pouring epoxy on a board like that?

"Terrible"


Could you qualify that opinion in terms of how it would negatively affect components?

I would understand that for example an antenna would be affected, or a component with exposed contacts like the sim-card holder, but what about sealed components?

Ifthis can work dipped in oil, then surely epoxy would not destroy it either right? I understand how it would create an insulating layer that would retain heat, but is this an issue on such a scale?


The oil filled PC is not under any high g-forces either.

Heat will not be a problem on a RF tracker or tag.
The epoxy will not affect the components as such other than wicking into the contact areas of connectors.

I was just kidding about the "terrible" comment.

I just think a casting with a less brittle property like a polyurethane base or silicone base would be better.
Think of a hammer hitting a super ball versus a hammer hitting a marble is the closest analogy I can come up with.

The casting epoxy you propose may work just fine.

edit: Fix spelling error for PS
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Last edited by dewey-1 on Wed Apr 25, 2012 1:09 pm, edited 1 time in total.
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Unread postAuthor: jackssmirkingrevenge » Wed Apr 25, 2012 10:53 am

dewey-1 wrote:The oil filled PC is not under any high g-forces either.


Yeah, I was just using it as an example of a coated board functioning.

Heat will not be a problem on a RF tracker or tag.
The epoxy will not effect (sic) the components as such other than wicking into the contact areas of connectors


The only "connectors" that should be involved are the battery contacts and those don't need to be potted if positioned well.

I just think a casting with a less brittle property like a polyurethane base or silicone base would be better.
Think of a hammer hitting a super ball versus a hammer hitting a marble is the closest analogy I can come up with.


I see your point, my idea though is to have the tag in a cast unit, then have this unit (cylindrical, travelling in the projectile body tube) packed between thick layers of memory foam to cushion against firing and impact forces - again pretty much what I had drawn here:

Image

edit: added note to quoted spelling error for POLAND_SPUD
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Last edited by jackssmirkingrevenge on Thu Apr 26, 2012 12:19 am, edited 1 time in total.
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Unread postAuthor: POLAND_SPUD » Wed Apr 25, 2012 11:05 am

he epoxy will not effect the components as such other than wicking into the contact areas of connectors.
affect!!
it's affect not effect



ImageI told you months ago to choose this design
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Unread postAuthor: jackssmirkingrevenge » Wed Apr 25, 2012 11:16 am

POLAND_SPUD wrote:it's affect not effect


oh come on, your posts are frequently riddled with spelling mistakes and we don't complain :)

I told you months ago to choose this design


I always insisted on it, then LeMaudit stepped in with his fantastic creation... but now I have my own machines :D
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Unread postAuthor: POLAND_SPUD » Wed Apr 25, 2012 11:43 am

oh come on, your posts are frequently riddled with spelling mistakes and we don't complain
Hey I am a pole - it's not surprising that I am often drunk
but he's a fuc#### native speaker for god's sake
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Unread postAuthor: al-xg » Wed Apr 25, 2012 12:04 pm

A bit harsh ???

The epoxy is only there to reduce strain on solder connections and movement between components, actual impact force reduction would be done by the foam, if it doesn't interfere with cooling or signal transmission I'd have thought it would be fine.
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Unread postAuthor: jackssmirkingrevenge » Wed Apr 25, 2012 12:53 pm

The epoxy is only there to reduce strain on solder connections and movement between components, actual impact force reduction would be done by the foam


Exactly how I see it, epoxy provides the structural integrity to keep the parts on the board together, but the board itself is then protected by thick layers of spongy material.
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Unread postAuthor: dewey-1 » Wed Apr 25, 2012 1:23 pm

POLAND_SPUD wrote:
he epoxy will not effect the components as such other than wicking into the contact areas of connectors.
affect!!
it's affect not effect


That is OK, PS can not even edit the the quote without a spelling error! :D

the not he


JSR
Here is a little information on the reasons for a "softer" potting compound.
You can do what you want but there are reasons for why I stated what I did about "hard" epoxies.

http://www.epicresins.com/electrical_control.asp
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